Agent based modeling (ABM) provides a means to analyze individual and social behavior, including the formation of coalitions of individuals, their adoption of ethnic and other norms, and the influence of ethnic and other affiliation on coalition members' behavior. Ethnic norms include shared beliefs and behaviors such as religious beliefs, dialects, modes of dress, ideology, and cuisine. Those sharing norms form a coalition of individuals who, at least sometimes, act out of group interest rather than short term individual interest. How coalitions emerge, when members adopt norms, what motivates individuals to join such groups, and how group membership influences behavior are issues that have become increasingly important to researchers in the social sciences. Recent successes in recruiting among terror groups and potential alliances among these groups represent security concerns regarding dynamics of coalition formation that may lead to social unrest, collective violence and/or terrorism. Despite revolutionary rhetoric, rebellions usually are started and led by the well-off.
Human ethnicity involves coalitions of individuals who adhere to norms of behavior. Anthropology is a particularly rich discipline in which to address questions of ethnic coalition formation, given the discipline's important cross-cultural comparative data on the formation and extinction of ethnic groups under a variety of environmental, social, and historical conditions.
Anthropologists have researched the origin of coalitions and the development of cultural norms from cultural ecology or human behavioral ecology research programs. In these programs, human behavior is seen as an evolutionary outcome of adapting to physical and social environments. Adaptive theories of coalition formation and ethnicity are grounded in rational choice, or bounded rationality theories. The methods anthropologists use include optimization, game theory, and computer simulation. Decision rules and other formulations are used to simulate and test proposed theories. In all cases, researchers propose that their models are on the whole, adaptive for meeting agents' material needs, even if agents sometimes adopt norms that fail in particular circumstances.
A drawback to these otherwise useful investigations is that researchers usually evaluate the performance of only one decision rule at a time, and usually over a limited number of iterations. Furthermore, competition for resources via genuinely competing strategies in large populations with varying environments usually has not been simulated or analyzed discretely. The discrete mathematics involved becomes intractable as dimensions or numbers of players increase and the entries in payoff matrices fluctuate. Instead, researchers commonly summarize the effects of model parameters with systems of differential equations and Lyapunov functions to produce more qualitative, global analyses of stability or convergence, ultimately obscuring coalitions and tending to analysis of mean behaviors and variances at best.
Competing theoretical claims of coalition and norm formation may be evaluated using computer simulations. These simulations shed light upon the emergence of ethnic and other affiliation and identification. To simulate the complexity of human social interaction, parallel processing computer clusters that have the computing power required for modeling large numbers of interacting agents may be used. Such simulations may model coalition formations and the development of norms under varying environmental conditions relevant to recent theories of ethnic group formation.
Advantageously, an illustrative ABM stimulation system can be used to evaluate the effects of numerous environmental conditions, simulate large populations, and accommodate more than one type of decision rule. The system can be used to evaluate propositions regarding human rationality and selfishness, develop simulation methodology for modeling coalition formation, and to advance substantive understanding of just how and why coalitions form or disperse. The simulation system provides a test bed for competing theories of macro- and micro-behaviors in dynamic games by controlling the fluctuations of environmental constraints, information constraints, and proximal interactions among agents. Post-simulation analysis provides, with some degree of confidence levels and reproducibility, measures of the model's sensitivity to parameters in payoff matrices, resource allocations, agent strategies and choices.
The use of such a system may have broad impacts for both education and policy. Policy implications involve shedding light on political Balkanization and the rise of ethnic identity in the post-Cold War world. The understanding of individual and coalition behaviors subject to fluctuating environmental constraints or controls is a necessary first step for applications in foreign affairs planning and domestic concerns, such as political action groups, criminal rings, and community organizations.
In accordance with the teachings of this disclosure, a method in a computer system for simulating individual and social behavior, includes: providing for creating a neighborhood of cells; providing for allocating resources to the cells; providing for assigning an agent to each cell; providing for selecting one of a plurality of decision rules for interactions between agents; providing for iteratively conducting discrete interactions between the agents using the selected decision rule and allocated resources; and providing for recording interaction outcome. The one of the plurality of decision rules may include a coordination game.
In accordance with the teachings of this disclosure, a computer-readable medium having machine-executable code for simulating the interactions of agents, includes: code for creating a neighborhood of cells; code for allocating resources to the cells; code for assigning an agent to each cell; code for selecting one of a plurality of decision rules for interactions between agents; code for iteratively conducting discrete interactions between the agents using the selected decision rule and allocated resources; and code for recording interaction outcome. The one of the plurality of decision rules may include a coordination game.
In accordance with the teachings of this disclosure, a system for agent based modeling, includes a computer and software enabling the computer to use a coordination game model to simulate and analyze the interactions of individual agents. The computer may include processors configured for parallel processing of the software.
In accordance with the teachings of this disclosure, a method of estimating the distribution of wealth in a population comprises applying the equation W(x)=e(d+ax+c sin(bx)), where a>bc. A method of estimating parameters of an expo-sigmoid model of wealth distribution comprises: creating a data set by taking the natural log of wealth data of a population; deriving a linear equation in the form of d+ax by performing an ordinary least squares regression of the data set; performing a fast-fourier transform on the residuals of the ordinary least squares regression; picking terms from the fast-fourier transform which are statistically significant to form a trigonometric polynomial in the form of f(x)=Σ cos(x)+sin(x); and constructing an equation estimating the wealth distribution of a population by calculating the exponential value of the sum of the linear terms and the trigonometric terms in the form of W(x)=e(d+ax+Σ cos(x)+sin(x)).
Additional features, which alone or in combination with any other feature(s), including those listed above and those listed in the claims, may comprise patentable subject matter and will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived.